All the fish you want are non-aggressive so IMO
you can add in any order.
I would go with either 3-5 chromis. They say odd numbers are best. I started with 7 and over the 3 years I had them I lost 5. I know have 2 and I tried to add 3 new ones and they were beat up by the 2 old ones.. They stay together all the time so they will school with smaller numbers.
I should ask how much LR
do you have and what types of mechanical filtration do you have..
Some will say you will be pushing the limits of the tank with 8 fish, Put IMO
they are small and with regular water changes you shold do well. BUT you will need good filtration, at least 40 lbs of LR
would be best.
Do you have a skimmer? Are you planning on one?